Psychological and emotional experiences of participants in a medical school, early assurance admissions program targeting students from groups underrepresented in medicine

BACKGROUND

There are growing number of pathway programs, with an early assurance of admission, that target undergraduate students from groups underrepresented in medicine (URiM) to enable their competitiveness for and matriculation to medical school, including the Penn Access Summer Scholars (PASS) program. The psychological and emotional experiences of students in these programs, however, have not been previously described.

METHODS

Students from the summer 2021 cohort of the PASS program were interviewed using a structured set of questions that explored four specific areas: (i) the application process; (ii) the benefits and value of being in the PASS program; (iii) the emotional and psychological challenges and stresses of being in the PASS program; (iv) feelings and emotions about not taking the MCAT or having to interview at multiple schools. The transcribed, de-identified interviews were then subjected to a qualitative analysis.

RESULTS

Students in PASS reported that the program was valuable to them in that it reduced the stress of the pre-medical process; relieved worry and anxiety surrounding the MCAT; enabled development of supportive relationships and provided meaningful exposures to the medical profession and biomedical research. Despite this, students reported feelings of imposterism, guilt, and fear of disappointing, along with varying degrees of regret over not taking the MCAT and not interviewing at more than one medical school.

CONCLUSIONS

URiM and other marginalized students participating in early assurance admissions programs likely enter medical school with a range of positive and negative emotions as a result of their participation in these programs. These data can be used to inform the development of programing and other initiatives that further support the transition and success of these students in medical school.

A 15-Year Analysis of Supply and Demand for Hematology and Oncology Training in the United States

PURPOSE

There is a paucity of research on the supply of the hematology and oncology workforce despite projected shortages in the United States Over the past 15 years of the hematology and oncology match (HOM), we hypothesized that there would be more growth in the number of training positions relative to applicants, higher match rates for US allopathic graduates relative to non-US allopathic graduates, and fewer applicants matching at their top fellowship choices.

METHODS

This was a national, retrospective cohort study of all applicants in the HOM (2009-2023). Match rates and applicant-to-training position ratios were calculated and compared over time with Pearson tests.

RESULTS

Growth in the number of annual training positions (426-708; 66% increase) exceeded growth in the number of interested applicants (706-945; 34% increase; P < .001). Annual applicant-to-training position ratios decreased from 1.7 to 1.3 (r = -0.813; P < .001). Match rates increased over the study period for both US allopathic graduates (79%-88%; r = 0.761; P = .001) and non-US allopathic graduates (45%-63%; r = 0.801; P < .001). During each year, match rates for US allopathic graduates exceeded those for non-US allopathic graduates (P < .001). From 2018 to 2023, US allopathic graduates (83%) had higher match rates than US osteopathic graduates (60%) and international medical graduates (50%; P < .001). The percentage of applicants that matched at one of their top three fellowship choices increased from 53% to 60% (r = 0.480; P = .070). Fewer available annual training positions went unfilled over the study period (3%-0.3%; r = - 0.870; P < .001).

CONCLUSION

Match rates have increased in the HOM but remain competitive especially for non-US allopathic graduates. Future investigation is needed to understand disparities in match outcomes by additional applicant and fellowship program characteristics. Ongoing surveillance of HOM outcomes remains critical given the projected shortages in the US hematology and oncology workforce.

Medical Students' Reflections on Their Experiences in a Trauma Chaplain Shadowing Program

The importance of spirituality in patient care is well recognized and efforts to develop educational opportunities to improve medical students' competency in spirituality and health are ongoing. In this regard, shadowing of healthcare chaplains has emerged as an experiential approach for providing exposure to and instruction in issues of spirituality in the patient experience and in patient care. Recently published data suggest that a 6-8 hour experience of shadowing a trauma chaplain is effective at introducing first-year medical students to healthcare chaplaincy, difficult spiritual conversations with patients and families, and interprofessional collaboration. As a follow-up to these data, this study provides a qualitative analysis of student reflections written immediately after their shadowing experience with the goal of further characterizing the educational impact of trauma chaplain shadowing. Qualitative analysis of 90 anonymous, student reflections indicated that trauma chaplain shadowing was an experience that provided insights about nature of chaplaincy, enabled opportunities to closely observe the relational skills of chaplains, allowed students to bear witness to suffering, fostered growth toward a professional identity, and facilitated recognition of shortcomings in medical education and clinical medicine. These data therefore provide further evidence of the value of chaplain shadowing in not only enhancing students' understanding of various dimensions of spirituality and medicine but also in promoting their development of a strong physician identity.

PAI-1 Deficiency Drives Pulmonary Vascular Smooth Muscle Remodeling and Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) is a progressive and potentially a rapidly fatal disease characterized by vasoconstriction and remodeling of small pulmonary arteries (PA) leading to increased pulmonary vascular resistance and right heart failure. Central to the remodeling process is a switch of the smooth muscle cells in small PAs (PASMC) to a proliferative, apoptosis-resistant phenotype. There is reason to suspect that the plasminogen activator system may play an important role in the remodeling program in PAH based on its roles in vascular post-injury restenosis, fibrosis, angiogenesis and tumorigenesis. Plasminogen activator inhibitor-1 (PAI-1) is the primary physiological inhibitor of the plasminogen activators - urokinase-type and tissue-type (uPA and tPA, respectively). Immunohisto- chemical and immunoblot analyses revealed that PAI-1 was deficient in smooth muscle areas of small remodeled PAs and early-passage PASMC from subjects with PAH compared to non-PAH controls. PAI1-/- male and female mice developed spontaneous pulmonary vascular remodeling and pulmonary hypertension (PH) as evidenced by significant increase in PA medial thickness, systolic right ventricular pressure, and right ventricular hypertrophy. Lastly, the uPA inhibitors upamostat (WX-671) and amiloride analog BB2-30F down-regulated mTORC1 and SMAD3, restored PAI-1 levels, reduced proliferation, and induced apoptosis in human PAH PASMC. We examined the effect of inhibition of uPA catalytic activity by BB2-30F on the development of SU5416/Hypoxia (SuHx)-induced PH in mice. Vehicletreated SuHx-exposed mice had up-regulated mTORC1 in small PAs, developed pulmonary vascular remodeling and PH, as evidenced by significant increase of PA MT, sRVP, RV hypertrophy, and a significant decrease in the pulmonary artery acceleration time/pulmonary ejection time (PAAT/PET) ratio compared to age- and sex-matched normoxia controls, whereas BB2-30F-treated group was protected from all these pathological changes. Taken together, our data strongly suggest that PAI-1 down- regulation in PASMC from human PAH lungs promotes PASMC hyper-proliferation, remodeling, and spontaneous PH due to unopposed uPA activation. Further studies are needed to determine the potential benefits of targeting the PAI-1/uPA imbalance to attenuate the progression and/or reverse pulmonary vascular remodeling and PH.

The medical humanities at United States medical schools: a mixed method analysis of publicly assessable information on 31 schools

INTRODUCTION

There have been increasing efforts to integrate the arts and humanities into medical education, particularly during undergraduate medical education (UME). Previous studies, however, have focused on courses and curricular programming without rigorous characterization of the associated paracurricular environment or infrastructure enabling or facilitating these offerings.

METHODS

To assess opportunities for students to engage the arts and humanities during their medical education as well as the institutional resources to support those opportunities, we developed the Humanities and Arts Programming Scale (HARPS): an 18-point scale involving eight sub-domains (Infrastructure, Curricular Opportunities, Extracurricular Engagement, Opportunities for Immersion, Faculty Engagement, Staff Support, Student Groups, and Scholarship). This scale was used to evaluate the top-31 ranked United States medical schools as determined by US News and World Report's (USWNR) Medical School Research Rankings using information derived from public-facing, online information.

RESULTS

Mean cumulative HARPS score was 11.26, with a median score of 12, a standard deviation of 4.32 and a score range of 3-17. Neither USWNR ranking nor private/public institution status were associated with the cumulative score (p = 0.121, p = 0.739). 52% of institutions surveyed had a humanities-focused center/division with more than 70% of the schools having significant (> 5) faculty engaged in the medical humanities. 65% of schools offered 10 or more paracurricular medical humanities events annually, while 68% of the institutions had more than 5 medical humanities student organizations. While elective, non-credit courses are available, only 3 schools required instruction in the arts and humanities, and comprehensive immersive experiences in the medical humanities were present in only 29% of the schools.

CONCLUSIONS

Although there is a significant presence of the medical humanities in UME, there is a need for integration of the arts and humanities into required UME curricula and into immersive pathways for engaging the medical humanities.

Defending Racial and Ethnic Diversity in Undergraduate and Medical School Admission Policies

This Viewpoint argues that reversing or restricting the use of race and ethnicity in academic admission policies could also threaten the diversity of medical schools, both directly by restricting race consciousness in medical school admission practices and indirectly by reducing the overall number of minoritized undergraduate students attending US colleges and universities who could apply to medical school.

Match Outcomes for Cardiovascular Disease Fellowship Training: 2010 to 2021

Background This study elucidates recent trends in application and match rates in the Cardiovascular Disease Fellowship Match. We hypothesized that (1) match rates have increased with time; (2) match rates are highest for US allopathic graduates; and (3) most candidates match at 1 of their top 3 ranked fellowship choices. Methods and Results This was a retrospective cohort study of all applicants in the Cardiovascular Disease Fellowship Match from 2010 to 2021 (n=14 674). Chi-square tests were used to compare trends over time and match rates by applicant archetype (US allopathic graduates and non-US allopathic graduates). The annual number of applicants increased from 1184 to 1575 (33% increase) while training positions increased 718 to 1045 (46% increase) over the study period. The percentage of applicants that matched increased from 61% in 2010 to 66% in 2021 (P=0.090). The average match rate was 70% over the study period. During each year, US allopathic graduates had higher match rates than non-US allopathic graduates (P<0.001), but this disparity narrowed with time (83% versus 41% in 2010 and 83% versus 54% in 2021). Most applicants matched at 1 of their top 3 choices (first, 37%; second, 12%; third, 7%). Applicants matching at 1 of their top 3 choices decreased from 51% in 2010 to 48% in 2021 (P=0.704). Conclusions The Cardiovascular Disease Fellowship Match has remained equally competitive over the past decade. US allopathic graduates have an advantage over non-US allopathic graduates. Most applicants match at 1 of their top 3 ranked fellowship choices.

Diversity, Equity, and Inclusion: Moving from Performance to Transformation Through the Arts and Humanities

Effective engagement on issues of diversity, equity, and inclusion (DEI) requires activities that promote deep introspection and group conversations that serve to complement and build upon formal DEI presentations. The arts and humanities by their nature allow for intentional and sustained reflection and have the potential to be transformative of thinking. We therefore propose that the next phase of institutional pro-equity/anti-racism efforts includes arts- and humanities-based initiatives to facilitate reflection and that serve to complement and build upon formal DEI didactic presentations, implicit bias workshops, and anti-racism training.

Tumor cell E-selectin ligands determine partialefficacy of bortezomib on spontaneous lung metastasis formation of solid human tumors in vivo

Extravasation of circulating tumor cells (CTCs) is critical for metastasis and is initiated by adhesive interactions between glycoligands on CTCs and E-selectin on endothelia. Here, we show that the clinically approved proteasome inhibitor bortezomib (BZM; Velcade) counteracts the cytokine-dependent induction of E-selectin in the lung mediated by the primary tumor, thereby impairing endothelial adhesion and thus spontaneous lung metastasis in vivo. However, the efficacy of BZM crucially depends on the tumor cells' E-selectin ligands, which determine distinct adhesion patterns. The canonical ligands sialyl-Lewis A (sLeA) and sLeX mediate particularly high-affinity E-selectin binding so that the incomplete E-selectin-reducing effect of BZM is not sufficient to disrupt adhesion or metastasis. In contrast, tumor cells lacking sLeA/X nevertheless bind E-selectin, but with low affinity, so that adhesion and lung metastasis are significantly diminished. Such low-affinity E-selectin ligands apparently consist of sialylated MGAT5 products on CD44. BZM no longer has anti-metastatic activity after CD44 knockdown in sLeA/X-negative tumor cells or E-selectin knockout in mice. sLeA/X can be determined by immunohistochemistry in cancer samples, which might aid patient stratification. These data suggest that BZM might act as a drug for inhibiting extravasation and thus distant metastasis formation in malignancies expressing low-affinity E-selectin ligands.

Food insecurity, type 2 diabetes, and hyperglycaemia: A systematic review and meta-analysis

AIMS

Food insecurity (FIS) is a major public health issue with possible implications for type 2 diabetes mellitus (T2DM) risk. We conducted a systematic review and meta-analysis to explore the association between FIS and T2DM.

METHODS

We performed a systematic search in PubMed, Embase, Scopus, and Web of Science. All cross-sectional, peer-reviewed studies investigating the link between FIS and T2DM were included. Population characteristics, study sizes, covariates, T2DM diagnoses, and diabetes-related clinical measures such as fasting blood glucose (FBG) and HbA1c were extracted from each study. Outcomes were compared between food insecure and food secure individuals. Effect sizes were combined across studies using the random effect model.

RESULTS

Forty-nine peer-reviewed studies investigating the link between FIS and T2DM were identified (n = 258,250). Results of meta-analyses showed no association between FIS and clinically determined T2DM either through FBG or HbA1c: OR = 1.22 [95%CI: 0.96, 1.55], Q(df = 5) = 12.5, I2  = 60% and OR = 1.21 [95%CI: 0.95, 1.54], Q(df = 5) = 14; I2  = 71% respectively. Standardized mean difference (SMD) meta-analyses yielded no association between FIS and FBG or HbA1c: g = 0.06 [95%CI: -0.06, 0.17], Q(df = 5) = 15.8, I2  = 68%; g = 0.11 [95% CI: -0.02, 0.25], Q(df = 7) = 26.8, I2  = 74% respectively. For children, no association was found between FIS and HbA1c: g = 0.06 [95%CI: 0.00, 0.17], Q(df = 2) = 5.7, I2  = 65%.

CONCLUSIONS

Despite multiple proposed mechanisms linking FIS to T2DM, integration of the available literature suggests FIS is not associated with clinically determined T2DM or increases in FBG or HbA1c among adult patients.

Chaplain Care in the Intensive Care Unit at the End of Life: A Qualitative Analysis

Background: The provision of spiritual care is a key component of high-quality patient-centered care, particularly in the intensive care unit (ICU). However, the integration of spiritual care into the care of patients in the ICU is variable, especially at the end of life, which may be due in part to poor or incomplete provider knowledge of the work of chaplains.

Objective: To characterize the care and services provided by chaplains to patients in an ICU at the end of life and/or their families.

Design: A retrospective chart review was performed to identify all patients admitted over a three-month period to an ICU who had visits with a chaplain and an ICU course that ended in death, discharge to a palliative care facility or discharge to hospice.

Subjects/setting: Twenty-five chaplains at a U.S. medical center.

Measurements: Qualitative analysis was performed using directed content analysis on the notes written by the chaplains.

Results: Qualitative analyses of the chaplain notes revealed four broad themes regarding the activities of chaplains in the ICU with respect to patients and families. These were that chaplains provide comfort to patients and family facing the end of life, provide prayers with a variety of purposes, assist in supporting family members through complex medical decision making, and provide connections to appropriate resources.

Conclusions: Chaplains contribute to the care of patients in the ICU through a wide range of activities that demonstrate the unique intermediary and collaborative role chaplains can play within the health care team at the end of life in the ICU.

Penn Access Summer Scholars program: a mixed method analysis of a virtual offering of a premedical diversity summer enrichment program

In the USA, numerous summer programs are available for undergraduate students that seek to increase the number of individuals from groups underrepresented in medicine (URM) that matriculate to medical school. These programs have typically been conducted at research-focused institutions, involving hands-on-research and various enrichment experiences. For 2020, the COVID-19 pandemic resulted in the suspension of on-campus student activities at American universities, necessitating a switch to a virtual format for these URM-focused programs. Outcomes, however, from these programs conducted virtually, necessitated by the COVID-19 pandemic, have not been reported. The Penn Access Summer Scholars (PASS) program at the Perelman School of Medicine (PSOM) targets URM undergraduates, providing two consecutive summers of mentored research and enrichment experiences, with the goal of enabling participants' matriculation to PSOM. PASS has been an 8 week on-campus experience, but during summer 2020, virtual programming of 6 weeks was provided due to the COVID-19 pandemic. Participants in the 2020 virtual offering of PASS completed pre- and post-program surveys that included 5-point Likert-style and open-ended questions to determine the impact of the programing on self-assessments of research skills, familiarity with the physician identity, and preparedness to be a PSOM student. Post-program, participants also assessed program administration and content. With respect to program objectives, participants reported significant increases in their self-reported confidence in conducting research, understanding of physician identity, and sense of preparedness for medical school. The educational value of the program content, their level of engagement in the program and the overall quality of the program were rated as excellent or outstanding by large majorities of respondents. Content analyses of participant comments were consistent with these quantitative results. Therefore, a premedical summer enrichment program targeting URM undergraduates can be successfully conducted virtually to achieve program objectives and may increase the availability to these initiatives.

Chaplain-Physician Interactions From the Chaplain's Perspective: A Mixed Method Analysis

BACKGROUND

The value of healthcare chaplains to patient care is increasingly recognized. However, physicians' understandings of the role of pastoral care have been reported to be poor, which have raised concerns about the quality of chaplain-physician interactions and their impact on patient care. These interactions, particularly from the perspective of the chaplain, have not been extensively investigated.

METHODS

An anonymous survey about the interactions of chaplains with physicians was sent to chaplains at a single institution, with subsequent focus group discussions of responding chaplains to obtain additional qualitative data.

RESULTS

Quantitative and qualitative data were collected from over 20 chaplains. While chaplains indicated satisfaction regarding their access to physicians, they noted a disconnect between chaplains and physicians, physicians' unfamiliarity with the chaplain role, a sense that physicians do not always appreciate the chaplain role as significant or helpful, and structural barriers to the integration of chaplains into medical care teams.

CONCLUSIONS

This study provides contemporary data on the nature of chaplain-physician interactions as reported from the perspective of chaplains. Further, these findings highlight opportunities for interventions to enhance the chaplain-physician relationship.

The "difficult" cadaver: weight bias in the gross anatomy lab

Background: The prevalence of overweight and obesity continues to rise and is associated with increased morbidity and mortality. Weight bias is common among physicians and medical students and limits the therapeutic alliance between providers and patients with overweight and obesity.Objective: The authors sought to explore the relationship between the gross anatomy course and medical student attitudes towards weight and obesity.Design: The authors employed a mixed-methods approach consisting of semi-structured interviews and anonymous web-based surveys of first-year medical students taking gross anatomy at one USA medical school. They analyzed transcripts of interviews and free-text survey responses using a grounded theory approach and performed tests of association to investigate the relationship between demographic information, responses to multiple-choice survey questions and weight bias.Results: A total of 319 (52%) first-year medical students (2015-2018) completed the survey and 33 participated in interviews. Of survey respondents, 71 (22%) responded that the course had changed how they felt about people with overweight/obesity. These respondents were also more likely to affirm that the course had affected their views toward their own bodies (p < 0.001). Qualitative data analysis identified three overarching themes within students' descriptions of the effects of the gross anatomy lab on attitudes toward bodies perceived to have excess weight: these bodies were described as 1) difficult, 2) unhealthy, and 3) evoking disgust. Students extrapolated from their experiences with cadavers to imagined interactions with future patients, relying heavily on the narrative of the difficult patient.Conclusions: At one USA medical school, students perceived their experiences in gross anatomy as shaping their attitudes toward individuals with overweight or obesity. Efforts to reduce medical student weight bias ought to target this previously unexplored potential site of weight bias.

Medical Students' Experience in a Trauma Chaplain Shadowing Program: A Mixed Method Analysis

Despite the importance of spirituality to health and patient care, there remains a lack of educational opportunities for medical students to learn about and engage the spiritual needs of patients. Shadowing of hospital chaplains has been employed as a means of providing instruction in spirituality, but published experiences of this pedagogy are limited. This study therefore analyzed an elective, first-year medical student, eight-hour, trauma chaplain shadowing experience, the objectives of which are to increase students' knowledge and understanding of (i) the role of chaplains/pastoral care in patient care; (ii) strategies for engaging patients and/or families in difficult situations; and (iii) approaches for discussing issues of spirituality with patients and families. Aquestionnaire was sent to participants after the experience assessing the value of the experience. Two focus groups provided additional qualitative data. Of the 148 participants over 6 years, 100 completed the questionnaire (68%). Participants on average engaged 1.78 trauma patients or their families and experienced 3.63 overall patient/family interactions during their shadowing. Over 90% of respondents agreed or strongly agreed that the experience provided agreater understanding of the role of the chaplain, and was educationally, professionally, and personally useful. Over 60% of respondents agreed or strongly agreed that the experience improved their understanding of discussing difficult or spiritual topics with patients and families. Nearly all respondents (98%) would recommend asimilar shadowing experience to fellow medical students. Qualitative remarks echoed these findings, revealing themes surrounding the educational benefits, surprise, and awe experienced by participants, and indicating appreciation for the interprofessional aspect of the experience. These data demonstrate that trauma chaplain shadowing may be effective for introducing first-year medical students to healthcare chaplaincy, educating them about the challenges of navigating difficult spiritual conversations with patients and families, and exposing them to interprofessional collaboration.

Food insecurity and hypertension: A systematic review and meta-analysis

Background

Food insecurity (FIS) is an important public health issue associated with cardiovascular risk. Given the association of FIS with diets of poorer nutritional quality and higher salt intake as well as chronic stress, numerous studies have explored the link between FIS and hypertension. However, no systematic review or meta-analysis has yet to integrate or analyze the existing literature.

Methods

We performed a wide and inclusive search of peer-reviewed quantitative data exploring FIS and hypertension. A broad-terms, systematic search of the literature was conducted in PubMed, Embase, Scopus, and Web of Science for all English-language, human studies containing primary data on the relationship between FIS and hypertension. Patient population characteristics, study size, and method to explore hypertension were extracted from each study. Effect sizes including odds ratios and standardized mean differences were extracted or calculated based on studies’ primary data. Comparable studies were combined by the random effects model for meta-analyses along with assessment of heterogeneity and publication bias.

Results

A total of 36 studies were included in the final analyses. The studies were combined into different subgroups for meta-analyses as there were important differences in patient population characteristics, methodology to assess hypertension, and choice of effect size reporting (or calculability from primary data). For adults, there were no significantly increased odds of elevated blood pressures for food insecure individuals in studies where researchers measured the blood pressures: OR = 0.91 [95%CI: 0.79, 1.04; n = 29,781; Q(df = 6) = 7.6; I² = 21%]. This remained true upon analysis of studies which adjusted for subject BMI. Similarly, in studies for which the standardized mean difference was calculable, there was no significant difference in measured blood pressures between food secure and FIS individuals: g = 0.00 [95%CI: -0.04, 0.05; n = 12,122; Q(df = 4) = 3.6; I² = 0%]. As for retrospective studies that inspected medical records for diagnosis of hypertension, there were no significantly increased odds of hypertension in food insecure adults: OR = 1.11 [95%CI: 0.86, 1.42; n = 2,887; Q(df = 2) = 0.7; I² = 0%]. In contrast, there was a significant association between food insecurity and self-reports of previous diagnoses of hypertension: 1.46 [95%CI: 1.13, 1.88; n = 127,467; Q(df = 7) = 235; I² = 97%]. Only five pediatric studies were identified which together showed a significant association between FIS and hypertension: OR = 1.44 [95%CI: 1.16, 1.79; n = 19,038; Q(df = 4) = 5.7; I² = 30%]. However, the small number of pediatric studies were not sufficient for subgroup meta-analyses based on individual study methodologies.

Discussion

In this systematic review and meta-analysis, an association was found between adult FIS and self-reported hypertension, but not with hypertension determined by blood pressure measurement or chart review. Further, while there is evidence of an association between FIS and hypertension among pediatric subjects, the limited number of studies precluded a deeper analysis of this association. These data highlight the need for more rigorous and longitudinal investigations of the relationship between FIS and hypertension in adult and pediatric populations.

Visual art instruction in medical education: a narrative review

The humanities have been increasingly incorporated into medical school curricula in order to promote clinical skills and professional formation. To understand its current use, we reviewed the literature on visual arts training in medical education, including relevant qualitative and quantitative data. Common themes that emerged from this review included a focus on preclinical students; instruction promoting observation, diagnostic skills, empathy, team building, communication skills, resilience, and cultural sensitivity. Successful partnerships have involved local art museums, with sessions led primarily by art educators employing validated pedagogy such as Visual Thinking Strategies or Artful Thinking. There is evidence that structured visual arts curricula can facilitate the development of clinical observational skills, although these studies are limited in that they have been single-institution reports, short term, involved small numbers of students and often lacked controls. There is a paucity of rigorous published data demonstrating that medial student art education training promotes empathy, team building, communication skills, wellness and resilience, or cultural sensitivity. Given these concerns, recommendations are offered for fostering more robust, evidence-based approaches for using visual arts instruction in the training of medical students.

Not Just a Specimen: A Qualitative Study of Emotion, Morality, and Professionalism in One Medical School Gross Anatomy Laboratory

Medical schools are increasingly integrating professionalism training into their gross anatomy courses, teaching ethical behavior and humanistic attitudes through the dissection experience. However, many schools continue to take a traditional, technical approach to anatomical education while teaching professionalism in separate courses. This interview-based study explored how students viewed the body donor and the professional lessons they learned through dissection at one such medical school. All students oscillated involuntarily between seeing the cadaver as a specimen for learning and seeing the cadaver as a person, with some students intentionally cultivating one of these ways of seeing over the other. These views shaped students' emotional and moral responses to the experiences of dissection. The "specimen" view facilitated a technical, detached approach to dissection, while the "person" view made students engage emotionally. Further, students who intentionally cultivated a "specimen" view generally felt less moral distress about dissection than students who intentionally cultivated a "person" view. The concept of respect gave students permission to perform dissections, but "person-minded" students developed more complex rules around what constituted respectful behavior. Both groups of students connected the gross anatomy experience to their professional development, but in different ways. "Specimen-minded" students intentionally objectified the body to learn the emotional control physicians need, while "person-minded" students humanized the body donor to promote the emotional engagement required of physicians. These findings support efforts to integrate professionalism teaching into gross anatomy courses, particularly content, addressing the balance between professional detachment and concern.

"Rebuilding what has eroded": a descriptive, survey-based study of near-peer instructors' experiences in a critical pedagogy-based sociomedical course

Purpose: Near-peer assisted learning has been deployed in numerous settings within medical education with promising results. However, there is very little experience utilizing near-peers in sociomedical or cultural competency training. We recently described a novel model for sociomedical learning based on Introduction to Medicine and Society (IMS), a critical pedagogy-based course at the Perelman School of Medicine at the University of Pennsylvania (PSOM). Near-peer facilitation, by senior medical students, is central to this model. The aim of this descriptive study is to examine how facilitating within this curriculum impacts senior medical students' self-reported attitudes toward course content, medical education, as well as self-care and medical practice. Methods: At the conclusion of the course, near-peer facilitator attitudes were assessed in three key domains through an anonymous survey. Attitudes were rated according to a 5-point Likert scale. Data from subgroups were analyzed using standard two-tailed t-tests. Optional narrative data were also collected. Results: Twenty six of 34 (76%) eligible facilitators completed the survey. Strong majorities of facilitators felt that their experience facilitating IMS had a favorable effect on attitudes related to course content (sociomedical issues and communication skills). A majority also endorsed favorable changes in their attitudes toward teaching and medical education. Large proportions of facilitators endorsed positive changes in a number of domains linked to trainee resilience. Conclusions: Our descriptive data suggest that acting as a near-peer facilitator as a senior medical student within a critical pedagogy-based course could help to fill multiple important curricular gaps at the transition from medical school to residency. Moreover, we find that a sociomedical facilitation experience during this important transition may increase enthusiasm for careers in medical education and undo some of the negative impacts of clinical training during medical school.

Trends in the Use of Common Words and Patient-Centric Language in the Titles of Medical Journals, 1976-2015

IMPORTANCE

The language of medical research appears to be intrinsically tied to the culture of medical research and provides a unique window into broader trends in the culture of medicine.

OBJECTIVE

To analyze medical language from 5 premier medical journals and investigate broader changes in the culture of clinical investigation during the last 40 years.

DESIGN, SETTING, AND PARTICIPANTS

In this qualitative study using a data-driven analysis, 302 293 PubMed records were extracted from JAMA, The Lancet, Annals of Internal Medicine, the BMJ, and New England Journal of Medicine from January 1, 1976, through December 31, 2015, to identify key trends in medical language. A frequency analysis was applied across the 40-year time frame in JAMA to assess the major trends in all publication types. Patient-centered language was analyzed in clinical trials in the flanking time periods (1976-1980 and 2011-2015) across the 5 journals. Data were analyzed from November 16, 2016, through November 9, 2018.

MAIN OUTCOMES AND MEASURES

Increasing or decreasing frequency of words (monograms) and word pairs (bigrams) and the proportion of patient-centric words in journal article titles.

RESULTS

In JAMA, 50 277 articles of all publication types were included. In the frequency analysis, the most increased terms were reflective of the language of epidemiological research. The bigram analysis revealed a decline in causal language (-2.42/100 000 words to -2.03/100 000 words; false discovery rate [FDR], <0.01) and an increased description of patients in the plural form (6.92/100 000 words to 11.4/100 000 words; FDR, <0.01). A trend to separate patient from disease was observed; for example, there was a decrease in describing a patient as a diabetic (-2.21/100 000 words; FDR, <0.01) compared with a patient with diabetes. In the analysis of clinical trials in all 5 journals, 3125 titles were identified (range, 193-932 per journal). In 4 of the 5 journals, use of patient-centric keywords increased significantly (absolute increase, 18.9%-34.3%; P < .001 for 3 journals; P = .01 for 1 journal), with the New England Journal of Medicine as the exception. This finding reflects a change from shorter disease-centric titles to longer titles that describe patients with a disease.

CONCLUSIONS AND RELEVANCE

Trends in medical language reflect the rise of evidence-based medicine, a shift in focus from individuals to populations, and a separation of patient and disease. Data-driven analysis of medical language provides a unique window into the changing landscape of medical culture.

The Fostering Resilience through Art in Medical Education (FRAME) workshop: a partnership with the Philadelphia Museum of Art

Background: Provider burnout remains a serious problem facing medical training programs and has been shown to affect more than half of internal medicine residents. In addition to broader efforts to revamp a health care system that contributes to this epidemic, exposure to the medical humanities offers potential to promote engagement, resilience, and restoration of meaning in residents' daily lives. Objective: We aim to create a reproducible, evidence-based workshop utilizing artful thinking routines to prepare trainees to combat burnout with reflection, perspective-taking, and community-building. Methods: A single, 4-hour workshop for senior internal medicine residents, centered on visual artistic analysis, was offered in June 2017 at the Philadelphia Museum of Art. Pre- and post-workshop burnout metrics and survey evaluation data were analyzed using a mixed-methods approach. Results: Workshop participation was offered to 29 internal medicine residents, of whom 17 (59%) participated. All survey respondents (n=13) rated the workshop as excellent and would recommend it to colleagues. Moderate decreases in the observed frequencies of both high emotional exhaustion scores (64.7% before the workshop to 55.5% following the workshop) and high depersonalization scores (70.6% before the workshop to 55.5% following the workshop) were observed. Conclusions: While results are preliminary in nature, the workshop was received favorably and demonstrated modest decreases in emotional exhaustion and depersonalization. We are encouraged to explore and repeat this workshop with modifications to identify its optimal position in the broader landscape of emerging wellness curricula.

The Receptor for Hyaluronan-Mediated Motility (CD168) promotes inflammation and fibrosis after acute lung injury

Acute lung injury results in early inflammation and respiratory distress, and later fibrosis. The glycosaminoglycan hyaluronan (HA) and the Receptor for Hyaluronan-Mediated Motility (RHAMM, CD168) have been implicated in the response to acute lung injury. We hypothesized that, compared to wild type (WT) mice, RHAMM knockout (KO) mice would be protected from, whereas mice with macrophage-specific transgenic overexpression of RHAMM (TG) would have worse inflammation, respiratory distress and fibrosis after intratracheal (IT) bleomycin. Compared to WT mice, 10 days after IT bleomycin, RHAMM KO mice had less weight loss, less increase in respiratory rate, and fewer CD45+ cells in the lung. At day 28, compared to injured WT animals, injured RHAMM KO mice had lower M1 macrophage content, as well as decreased fibrosis as determined by trichrome staining, Ashcroft scores and lung HPO content. Four lines of transgenic mice with selective overexpression of RHAMM in macrophages were generated using the Scavenger Receptor A promoter driving a myc-tagged full length RHAMM cDNA. Baseline expression of RHAMM and CD44 was the same in WT and TG mice. By flow cytometry, TG bone marrow-derived macrophages (BMDM) had increased cell surface RHAMM and myc, but equal CD44 expression. TG BMDM also had 2-fold increases in both chemotaxis to HA and proliferation in fetal bovine serum. In TG mice, increased inflammation after thioglycollate-induced peritonitis was restricted to macrophages and not neutrophils. For lung injury studies, non-transgenic mice given bleomycin had respiratory distress with increased respiratory rates from day 7 to 21. However, TG mice had higher respiratory rates from 4 days after bleomycin and continued to increase respiratory rates up to day 21. At 21 days after IT bleomycin, TG mice had increased lung macrophage accumulation. Lavage HA concentrations were 6-fold higher in injured WT mice, but 30-fold higher in injured TG mice. At 21 days after IT bleomycin, WT mice had developed fibrosis, but TG mice showed exaggerated fibrosis with increased Ashcroft scores and HPO content. We conclude that RHAMM is a critical component of the inflammatory response, respiratory distress and fibrosis after acute lung injury. We speculate that RHAMM is a potential therapeutic target to limit the consequences of acute lung injury.

Involvement of TIMP-1 in PECAM-1-mediated tumor dissemination

Platelet endothelial cell adhesion molecule-1 (PECAM-1) is expressed on the vascular endothelium and has been implicated in the late progression of metastatic tumors. The activity of PECAM-1 appears to be mediated by modulation of the tumor microenvironment (TME) and promotion of tumor cell proliferation, rather than through the stimulation of tumor angiogenesis. The present study aimed to extend those initial findings by indicating that the presence of functional PECAM-1 on the endothelium promotes a proliferative tumor cell phenotype in vivo, as well as in tumor cell (B16-F10 melanoma and 4T1 breast cancer cell lines) co-culture assays with mouse endothelial cells (ECs) or a surrogate EC line (REN-MP). The pro-proliferative effects were mediated by soluble endothelial-derived factors that were dependent on PECAM-1 homophilic ligand interactions, but which were independent of PECAM-1-dependent signaling. Further analysis of the conditioned media obtained from tumor/EC and tumor/REN-MP co-cultures identified TIMP metallopeptidase inhibitor-1 (TIMP-1) as a PECAM-1-regulated factor, the targeting of which in the tumor cell/REN-MP system inhibited tumor cell proliferation. In addition, TIMP-1 expression was decreased in metastatic tumors from the lungs of PECAM-1-null mice, thus providing evidence of the in vivo significance of co-culture studies. Taken together, these studies indicated that endothelial PECAM-1, through PECAM-1-dependent homophilic binding interactions, may induce release of TIMP-1 from the endothelium into the TME, thus leading to increased tumor cell proliferation.

Influence of PECAM-1 ligand interactions on PECAM-1-dependent cell motility and filopodia extension

Platelet endothelial cell adhesion molecule (PECAM‐1) has been implicated in angiogenesis through processes that involve stimulation of endothelial cell motility. Previous studies suggest that PECAM‐1 tyrosine phosphorylation mediates the recruitment and then activation of the tyrosine phosphatase SHP‐2, which in turn promotes the turnover of focal adhesions and the extension of filopodia, processes critical to cell motility. While these studies have implicated PECAM‐1‐dependent signaling in PECAM‐1‐mediated cell motility, the involvement of PECAM‐1 ligand binding in cell migration is undefined. Therefore to investigate the role of PECAM‐1 binding interactions in cell motility, mutants of PECAM‐1 were generated in which either homophilic or heparin/glycosaminoglycan (GAG)‐mediated heterophilic binding had been disabled and then expressed in an endothelial cell surrogate. We found that the ability of PECAM‐1 to stimulate cell migration, promote filopodia formation and trigger Cdc42 activation were lost if PECAM‐1‐dependent homophilic or heparin/GAG‐dependent heterophilic ligand binding was disabled. We further observed that PECAM‐1 concentrated at the tips of extended filopodia, an activity that was diminished if homophilic, but not heparin/GAG‐mediated heterophilic binding had been disrupted. Similar patterns of activities were seen in mouse endothelial cells treated with antibodies that specifically block PECAM‐1‐dependent homophilic or heterophilic adhesion. Together these data provide evidence for the differential involvement of PECAM‐1‐ligand interactions in PECAM‐1‐dependent motility and the extension of filopodia.

Best Practices in Relational Skills Training for Medical Trainees and Providers: An Essential Element of Addressing Adverse Childhood Experiences and Promoting Resilience

Medical providers' ability to form strong therapeutic alliances with patients is an essential clinical skill that is associated with a higher quality of care and improved provider well-being. However, comparatively few medical providers exhibit adequate relational skills, which serve to convey respect, communicate caring, and build trust between the medical provider and the patient. A growing number of medical training programs and continuing medical education programs have begun to incorporate relational skills training, but the results have been highly variable in terms of training methods and effect. To support administrators who are considering the implementation (or improvement) of relational skills training in their organization, we provide a set of best practices for relational skills training, in the basis of a review of the literature and on our experience as clinical educators, and show the application of these best practices through a case study. We conclude with a discussion of challenges for implementing a high-quality relational skills training program, policy-level solutions for these challenges, and recommendations for future research.

Integrating Theory, Content, and Method to Foster Critical Consciousness in Medical Students: A Comprehensive Model for Cultural Competence Training

Many efforts to design introductory "cultural competence" courses for medical students rely on an information delivery (competence) paradigm, which can exoticize patients while obscuring social context, medical culture, and power structures. Other approaches foster a general open-minded orientation, which can remain nebulous without clear grounding principles. Medical educators are increasingly recognizing the limitations of both approaches and calling for strategies that reenvision cultural competence training. Successfully realizing such alternative strategies requires the development of comprehensive models that specify and integrate theoretical frameworks, content, and teaching principles.In this article, the authors present one such model: Introduction to Medicine and Society (IMS), a required cultural competence course launched in 2013 for first-year medical students at the Perelman School of Medicine at the University of Pennsylvania. Building on critical pedagogy, IMS is centered on a novel specification of "critical consciousness" in clinical practice as an orientation to understanding and pragmatic action in three relational domains: internal, interpersonal, and structural. Instead of transmitting discrete "facts" about patient "types," IMS content provokes students to engage with complex questions bridging the three domains. Learning takes place in a small-group space specifically designed to spur transformation toward critical consciousness. After discussing the three key components of the course design and describing a representative session, the authors discuss the IMS model's implications, reception by students and faculty, and potential for expansion. Their early experience suggests the IMS model successfully engages students and prepares future physicians to critically examine experiences, manage interpersonal dynamics, and structurally contextualize patient encounters.

Isolation of endothelial cells from mouse lung

The isolation of endothelial cells (ECs) from knockout and transgenic mouse lines provides the opportunity to study the endothelial-specific activities of a targeted molecule. As a means of pursuing these types of investigations, the protocols described in this unit provide a reliable method for isolating lung microvascular ECs from mouse neonatal pups that can be serially passaged. These protocols are useful in settings where mouse age is irrelevant and a pure population of pulmonary vascular ECs, uncontaminated by other cells, is needed. When a specific source of ECs is not required, these procedures also represent a reliable means of obtaining murine ECs in general.

NEU1 sialidase regulates the sialylation state of CD31 and disrupts CD31-driven capillary-like tube formation in human lung microvascular endothelia

The highly sialylated vascular endothelial surface undergoes changes in sialylation upon adopting the migratory/angiogenic phenotype. We recently established endothelial cell (EC) expression of NEU1 sialidase (Cross, A. S., Hyun, S. W., Miranda-Ribera, A., Feng, C., Liu, A., Nguyen, C., Zhang, L., Luzina, I. G., Atamas, S. P., Twaddell, W. S., Guang, W., Lillehoj, E. P., Puché, A. C., Huang, W., Wang, L. X., Passaniti, A., and Goldblum, S. E. (2012) NEU1 and NEU3 sialidase activity expressed in human lung microvascular endothelia. NEU1 restrains endothelial cell migration whereas NEU3 does not. J. Biol. Chem. 287, 15966-15980). We asked whether NEU1 might regulate EC capillary-like tube formation on a Matrigel substrate. In human pulmonary microvascular ECs (HPMECs), prior silencing of NEU1 did not alter tube formation. Infection of HPMECs with increasing multiplicities of infection of an adenovirus encoding for catalytically active WT NEU1 dose-dependently impaired tube formation, whereas overexpression of either a catalytically dead NEU1 mutant, NEU1-G68V, or another human sialidase, NEU3, did not. NEU1 overexpression also diminished EC adhesion to the Matrigel substrate and restrained EC migration in a wounding assay. In HPMECs, the adhesion molecule, CD31, also known as platelet endothelial cell adhesion molecule-1, was sialylated via α2,6-linkages, as shown by Sambucus nigra agglutinin lectin blotting. NEU1 overexpression increased CD31 binding to Arachis hypogaea or peanut agglutinin lectin, indicating CD31 desialylation. In the postconfluent state, when CD31 ectodomains are homophilically engaged, NEU1 was recruited to and desialylated CD31. In postconfluent ECs, CD31 was desialylated compared with subconfluent cells, and prior NEU1 silencing completely protected against CD31 desialylation. Prior CD31 silencing and the use of CD31-null ECs each abrogated the NEU1 inhibitory effect on EC tube formation. Sialyltransferase 6 GAL-I overexpression increased α2,6-linked CD31 sialylation and dose-dependently counteracted NEU1-mediated inhibition of EC tube formation. These combined data indicate that catalytically active NEU1 inhibits in vitro angiogenesis through desialylation of its substrate, CD31.

Case writing as a vehicle for promoting cultural competency: a retrospective, descriptive qualitative analysis

BACKGROUND

A variety of approaches are available that provide cultural competency education for practicing physicians. There is, however, still a need for additional, innovative approaches that address continuing education and professional improvement regarding cultural competency for physicians after their training.

OBJECTIVE

To assess the potential impact on established clinicians of writing an extended case narrative on cultural competency.

METHODS

We conducted structured interviews of physician contributors (n = 14) to a book of cases on cultural competency. Authors were invited to contribute to the book based on their experiences as established clinicians, and previous expertise in cultural competency research or education was not required. Because of this, the editors employed a process in which they worked with contributors in a one-on-one manner to develop their case(s).

RESULTS

The participants were experienced physicians (all > 10 years since medical school graduation), most of whom were white (64%) and affiliated with an academic medical center (86%). The majority of the contributors (1) reported that writing their case(s) increased their awareness of, and sensitivity to, issues of cultural competency; (2) indicated that the writing of their case(s) changed their approach to patient care and/ or their education of medical students or graduate medical trainees; and (3) would recommend case writing as a vehicle for promoting cultural sensitivity and awareness.

CONCLUSIONS

Although preliminary, these data suggest that the cultural awareness, sensitivity, and competence of established physicians might be enhanced by a process in which clinicians are facilitated in the writing of cases that address issues of culture that are pertinent to their practice and patient experiences.

Collaborative enhancement of antibody binding to distinct PECAM-1 epitopes modulates endothelial targeting

Antibodies to platelet endothelial cell adhesion molecule-1 (PECAM-1) facilitate targeted drug delivery to endothelial cells by “vascular immunotargeting.” To define the targeting quantitatively, we investigated the endothelial binding of monoclonal antibodies (mAbs) to extracellular epitopes of PECAM-1. Surprisingly, we have found in human and mouse cell culture models that the endothelial binding of PECAM-directed mAbs and scFv therapeutic fusion protein is increased by co-administration of a paired mAb directed to an adjacent, yet distinct PECAM-1 epitope. This results in significant enhancement of functional activity of a PECAM-1-targeted scFv-thrombomodulin fusion protein generating therapeutic activated Protein C. The “collaborative enhancement” of mAb binding is affirmed in vivo, as manifested by enhanced pulmonary accumulation of intravenously administered radiolabeled PECAM-1 mAb when co-injected with an unlabeled paired mAb in mice. This is the first demonstration of a positive modulatory effect of endothelial binding and vascular immunotargeting provided by the simultaneous binding a paired mAb to adjacent distinct epitopes. The “collaborative enhancement” phenomenon provides a novel paradigm for optimizing the endothelial-targeted delivery of therapeutic agents.

Modulators of endothelial cell filopodia: PECAM-1 joins the club

Filopodia are an important feature of actively motile cells, probing the pericellular environment for chemotactic factors and other molecular cues that enable and direct the movement of the cell. They also act as points of attachment to the extracellular matrix for the cell, generating tension that may act to pull the cell forward and/or stabilize the cell as it moves. Endothelial cell motility is a critical aspect of angiogenesis, but only a limited number of molecules have been identified as specific regulators of endothelial cell filopodia. Recent reports, however, provide evidence for the involvement of PECAM-1, an endothelial cell adhesion and signaling molecule, in the formation of endothelial cell filopodia. This commentary will focus on these studies and their suggestion that at least two PECAM-1-regulated pathways are involved in the processes that enable filopodial protrusions by endothelial cells. Developing a more complete understanding of the role of PECAM-1 in mediating various endothelial cell activities, such as the extension of filopodia, will be essential for exploiting the therapeutic potential of targeting PECAM-1.

A practical approach to the family that expects a miracle

When a patient is extremely ill and/or dying, and the family expects a miraculous recovery, this situation can be very challenging to physicians, particularly when there is certainty that the miracle will occur through divine intervention. A practical approach is therefore provided to clinicians for engaging families that anticipate the miraculous healing of a sick patient. This strategy involves exploring the meaning and significance of a miracle, providing a balanced, nonargumentative response and negotiation of patient-centered compromises, while conveying respect for patient spirituality and practicing good medicine. Such an approach, tailored to the specifics of each family, can be effective in helping a family come to a place of acceptance about the impending death of their loved one.

Luteogenic hormones act through a vascular endothelial growth factor-dependent mechanism to up-regulate alpha 5 beta 1 and alpha v beta 3 integrins, promoting the migration and survival of human luteinized granulosa cells

The formation of the corpus luteum (CL) is critical for the establishment of a successful pregnancy. After ovulation, the CL develops from the remnants of the ovulated ovarian follicle. This process, which involves varying cell-matrix interactions, is poorly characterized. To understand the role and potential regulation of cell-matrix interactions in the formation of the CL, we investigated the expression and activity of the matrix protein fibronectin (FN) and several of its integrin receptors on luteinized granulosa cells (GCs). In situ, FN and several FN-binding integrins were detected around luteinizing GCs during the early luteal phase, although expression declined in the late luteal phase. In vitro, GCs released FN, and stimulation of these cells with human chorionic gonadotropin increased the surface expression of FN, alpha(5)beta(1), and alpha(v)beta(3). Up-regulation of these proteins on GCs was reproduced by stimulation with vascular endothelial growth factor (VEGF) and was inhibited by anti-VEGF antibody. Lastly, expression of alpha(5)beta(1) and alpha(v)beta(3) mediated adhesion to FN, facilitated migration, and prevented apoptosis. These data suggest that in vivo luteogenic hormones, in part through a VEGF-dependent mechanism, stimulate selected integrin-matrix adhesive interactions that promote the motility and survival of GCs and thus contribute to the formation and preservation of the CL.

c7E3 Fab inhibits human tumor angiogenesis in a SCID mouse human skin xenograft model

The alphavbeta3 integrin plays an important role in tumor growth and angiogenesis. Inhibition of this receptor by intact bivalent antibodies has been shown to inhibit angiogenesis and tumor growth. In this study we tested the chimeric Fab of 7E3 (c7E3 Fab), an antibody reactive with human platelet GPIIb/IIIa and alphavbeta3 to determine if it would inhibit in vivo angiogenesis and tumor growth in a SCID mouse/human skin tumor growth and angiogenesis model. c7E3 Fab inhibited human tumor angiogenesis and tumor growth. These data suggest monovalent antibody fragments devoid of antibody effector function can have efficacy in preclinical models of angiogenesis.

Loss of PECAM-1 function impairs alveolarization

The final stage of lung development in humans and rodents occurs principally after birth and involves the partitioning of the large primary saccules into smaller air spaces by the inward protrusion of septae derived from the walls of the saccules. Several observations in animal models implicate angiogenesis as critical to this process of alveolarization, but all anti-angiogenic treatments examined to date have resulted in endothelial cell (EC) death. We therefore targeted the function of platelet endothelial cell adhesion molecule, (PECAM-1), an EC surface molecule that promotes EC migration and has been implicated in in vivo angiogenesis. Administration of an anti-PECAM-1 antibody that inhibits EC migration, but not proliferation or survival in vitro, disrupted normal alveolar septation in neonatal rat pups without reducing EC content. Three-dimensional reconstruction of lungs showed that pups treated with a blocking PECAM-1 antibody had remodeling of more proximal branches resulting in large tubular airways. Subsequent studies in PECAM-1-null mice confirmed that the absence of PECAM-1 impaired murine alveolarization, without affecting EC content, proliferation, or survival. Further, cell migration was reduced in lung endothelial cells isolated from these mice. These data suggest that the loss of PECAM-1 function compromises postnatal lung development and provide evidence that inhibition of EC function, in contrast to a loss of viable EC, inhibits alveolarization.

Role of immunoreceptor tyrosine-based inhibitory motifs of PECAM-1 in PECAM-1-dependent cell migration

Platelet endothelial cell adhesion molecule (PECAM-1), a transmembrane glycoprotein, has been implicated in angiogenesis, with recent evidence indicating the involvement of PECAM-1 in endothelial cell motility. The cytoplasmic domain of PECAM-1 contains two tyrosine residues, Y663 and Y686, that each fall within an immunoreceptor tyrosine-based inhibitory motif (ITIM). When phosphorylated, these residues together mediate the binding of the protein tyrosine phosphatase SHP-2. Because SHP-2 has been shown to be involved in the turnover of focal adhesions, a phenomenon required for efficient cell motility, the association of this phosphatase with PECAM-1 via its ITIMs may represent a mechanism by which PECAM-1 might facilitate cell migration. Studies were therefore done with cell transfectants expressing wild-type PECAM or mutant PECAM-1 in which residues Y663 and Y686 were mutated. These mutations eliminated PECAM-1 tyrosine phosphorylation and the association of PECAM-1 with SHP-2 but did not impair the ability of the molecule to localize at intercellular junctions or to bind homophilically. However, in vitro cell motility and tube formation stimulated by the expression of wild-type PECAM-1 were abrogated by the mutation of these tyrosine residues. Importantly, during wound-induced migration, the number of focal adhesions as well as the level of tyrosine phosphorylated paxillin detected in cells expressing wild-type PECAM-1 were markedly reduced compared with control cells or transfectants with mutant PECAM-1. These data suggest that, in vivo, the binding of SHP-2 to PECAM-1, via PECAM-1's ITIM domains, promotes the turnover of focal adhesions and, hence, endothelial cell motility.

Antibody against murine PECAM-1 inhibits tumor angiogenesis in mice

Platelet endothelial cell adhesion molecule (PECAM-1/CD31), a member of the immunoglobulin superfamily expressed at high levels on endothelial cells, has been recently implicated in angiogenesis. Although antagonism of PECAM-1 inhibited neovascularization in two different animal models of growth factor/chemokine-induced angiogenesis, its participation in tumor angiogenesis has not been established. We therefore investigated its involvement in models of tumor angiogenesis in mice. An antibody against murine PECAM-1 that was shown to block in vitro murine endothelial tube formation inhibited the subcutaneous growth and tumor vascularity of three tumors in mice: A549 human non-small cell lung cancer in SCID mice, B16 murine melanoma in C57BL/6 mice and AB12 murine mesothelioma in Balb/c mice. These studies suggest a possible role for PECAM-1 in the complex process of tumor angiogenesis and provide additional evidence of the importance of endothelial cell adhesion molecules to the formation of new vessels.

Platelet endothelial cell adhesion molecule-1 in neutrophil emigration during acute bacterial pneumonia in mice and rats

Platelet endothelial cell adhesion molecule-1 (PECAM-1) (CD31) is an adhesion molecule believed to mediate transendothelial migration of neutrophils and other leukocytes after CD11/CD18-mediated adhesion. Our study evaluated the role of PECAM-1 in neutrophil emigration across the pulmonary capillaries and the bronchial microvasculature using blocking anti-PECAM-1 antibodies in mice and rats. Neutrophil emigration was induced by Escherichia coli, a stimulus eliciting CD11/CD18-dependent emigration, or Streptococcus pneumoniae, a stimulus inducing CD11/CD18-independent emigration. Although anti-PECAM-1 antibodies partially inhibited glycogen-induced neutrophil emigration into the peritoneum, neutrophil emigration across either the pulmonary capillaries or the bronchial microvasculature in response to either E. coli or S. pneumoniae was not prevented when the function of PECAM-1 was inhibited in either mice or rats. There was also no increase in the number of intravascular neutrophils within the bronchial vessels after treatment with anti-PECAM-1 antibody. These studies indicate that either CD11/CD18-dependent or -independent adhesion pathways may lead to PECAM-1-independent transendothelial migration through the pulmonary or the bronchial endothelium.

Vascular endothelial growth factor and Kaposi's sarcoma cells in human skin grafts

Human cancer cells often produce tumors in animal models that incompletely reproduce the histology of the parental tumor. Kaposi's sarcoma (KS) cells, in particular, have not produced durable angiogenic lesions in animal models that resemble those of KS in humans. We investigated the contribution of transformed KS cells, vascular endothelial growth factor (VEGF), and human skin tissue on tumor development in a human skin graft/mouse model. High levels of serum VEGF (322 pg/ml) were seen in HIV-1-infected persons with KS compared with HIV-1-infected persons without KS (115 pg/ml). Human KS lesions expressed VEGF in the spindle cells. Transformed KS cells expressed the mitogenically active 121-amino acid and 165-amino acid isoforms of VEGF. Tumors induced by KS cells implanted in the SCID mice grew preferentially in human skin grafts rather than in ungrafted murine skin. Tumors induced in the presence of human skin grafts developed numerous lumens expressing alpha(v)beta(3) integrin. KS cells inoculated with neutralizing anti-VEGF antibody did not form tumors. This study supports an important role for VEGF in tumor development and shows how a human tissue can preferentially promote tumor growth.